Glentoran kept up their challenge for a European place by seeing off the challenge of Dungannon at the Oval.
Curtis Allen scored at the second attempt, finding the bottom corner with a left-foot shot in the 19th minute for his 15th league goal of the campaign.
Barry Holland's cross from the right was met by Stephen McAlorum's diving header 11 minutes into the second half.
The Glens have won all four meetings between the sides this season and lie fifth in the Premiership standings.
Eddie Patterson's side began brightly and Allen, scorer of the only goal in last week's Irish Cup semi-final win over Crusaders, twice tested Marty Gallagher in the Swifts' goal.
Kym Nelson picked out Allen in the box for the opener and before the break, Jordan Stewart found the back of the net with a header, but the flag was up for offside.
McAlorum's well-executed finish made the points safe for the hosts.